80C186EC/80C188EC Microprocessor User's Manual

INSTRUCTION SET DESCRIPTIONS
Table C-4. Instruction Set (Continued)
Name Description Operation
Flags
Affected
JO
JP
JPE
JS
LAHF
NOTE:
Jump on Overflow:
JO disp8
Transfers control to the target location
if the tested condition (OF = 1) is true.
Instruction Operands:
JO short-label
Jump on Parity:
Jump on Parity Equal:
JP disp8
JPE disp8
Transfers control to the target location
if the tested condition (PF = 1) is true.
Instruction Format:
JP short-label
JPE short-label
Jump on Sign:
JS disp8
Transfers control to the target location
if the tested condition (SF = 1) is true.
Instruction Format:
JS short-label
Load Register AH From Flags:
LAHF
Copies SF, ZF, AF, PF and CF (the
8080/8085 flags) into bits 7, 6, 4, 2 and
0, respectively, of register AH. The
content of bits 5, 3, and 1 are
undefined. LAHF is provided primarily
for converting 8080/8085 assembly
language programs to run on an 8086
or 8088.
Instruction Operands:
none
if
(OF) = 1
then
(IP) ← (IP) + disp8 (sign-ext to 16 bits)
if
(PF) = 1
then
(IP) ← (IP) + disp8 (sign-ext to 16 bits)
if
(SF) = 1
then
(IP) ← (IP) + disp8 (sign-ext to 16 bits)
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
(AH) ← (SF):(ZF):X:(AF):X:(PF):X:(CF) AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
The three symbols used in the Flags Affected column are defined as follows:
– the contents of the flag remain unchanged after the instruction is executed
the contents of the flag is undefined after the instruction is executed
üthe flag is updated after the instruction is executed
C-25